Electric Motors/loud noises


QUESTION: can a bad thermostat cause a loud whine or is it another problem

ANSWER: Well I need more details but in general    I have to assume you are talking about your home AC OR HEAT OR BOTH<

Right off the bat,  I doubt a thermostat is causing a whine, most likely the blower motor when the furnace or ac calls for cooling or heat,   nothing in the thermostat to whine,  but you have a reason to think it might,  so I dont discount anything,    but I would look to the blower first       

send me more detailed info,   when it started where you hear the whining,   anything you can think of might mean something,      

it may be no more than a can of 3-1 oil in the oil wick holes in the blower motor,    

But send me more details   


---------- FOLLOW-UP ----------

QUESTION: why would it be louder at times

Many blower motors have one or more sleeve or plain bearings,   they tend to wear on the journal and sometimes it is simply thermal growth when the motor works up to operating temp,    or even ball bearings can do that,   the rotor will tend to slide or strike, not so much when cold but when hot,   is a good sign it is the bearings,   but it could be other things,  it depends on the type of furnace, if you have draft fans or just a blower only,  one of the draft fans can start squeaking,  from time to time,        it is really hard to say,  even something that fell down a register at some point can become dislodged and make noises now and then,    

But since a thermostat has no moving parts,  it is unlikely it is that,   not saying it is out of the question, but it would be low on the list of probable causes,   

You will need to stand by the blower unit, and hopefully you can get a better idea of where the sound is coming from,   

Remember  anything that is making the noise does it at a specific frequency or resonance,  and that can cause other pieces and parts that move at the same frequency   [not the now and then but operating frequency]

Try and be at the blower unit when it calls for heat   I am assuming,     it could be cool form, AC in some parts of the country  but whatever the reason the blower assembly is where to look first,     let me know how you get along   we will figure it out,


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Three phase/ AC DC single phase motors, controls, any problems or failures, motor installation, performance issues, connections. All other electric motors/gearboxes/apparatus. Specialty repair concerns, obsolete motors and solutions. Other mechanical or specialty equipment. See my profile under Home/electrical at this site


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